1. Field of the Invention
The present invention relates to an image trimming method and an image trimming apparatus for automatically trimming an image obtained by a photography apparatus, such as a digital camera. The present invention also relates to a program for the image trimming method and the image trimming apparatus.
2. Description of the Related Art
Conventionally, trimming processing has been performed by cutting out a part of a photograph image obtained by a photography apparatus, such as a digital camera. The trimming processing is processing for correcting the composition of the photograph image to composition intended by the photographer of the photograph image or to objectively more desirable composition. Further, such trimming processing can be relatively easily performed using general computer software for image processing.
However, when a general user performs trimming processing, it is difficult to judge what kind of composition is objectively most desirable. Further, there is also a problem that the operation of software for setting a trimming range (trimming region) is complicated.
To solve such problems, a method for automatically setting a trimming range that is appropriate for an image has been proposed. In the method for automatically setting the trimming range, the trimming range is set by analyzing the characteristic of a photograph image or photography conditions. For example, a trimming method has been proposed in Japanese Unexamined Patent Publication No. 2005-175684. In the method proposed in Japanese Unexamined Patent Publication No. 2005-175684, a photographer selects the photography mode (portrait mode/scenery mode) of a photography apparatus. Then, an image analysis that is appropriate for the selected photography mode is made on an image obtained by photography, and a trimming range of the image obtained by photography is determined based on the result of the analysis. Then, trimming is performed based on the trimming range.
However, even if as disclosed in Japanese Unexamined Patent Publication No. 2005-175684, the characteristic of an image obtained by photography is analyzed and a trimming range is determined based on the result of the analysis, the intention of a photographer at the time of photography might not be sufficiently reflected in an image obtained by trimming. Therefore, the composition of the image might not sufficiently satisfy users in some cases.
For example, most of currently-sold photography apparatuses, such as digital cameras, have zoom functions. When the composition of an image obtained by such a photography apparatus is a relatively wide angle composition, it is impossible to judge whether the photographer of the image intentionally selected the wide angle composition without zooming or the composition of the image became the wide angle composition because the performance of the zoom function of the photography apparatus was limited. Hence, it is impossible to perform desirable trimming in some cases.
FIG. 7 is a diagram illustrating an example of two photograph images of the same scene but with different composition. The composition of image Pz is relatively wide angle composition with respect to persons who are the subject of photography. A plurality of children playing football (soccer) is in the whole photograph image. Meanwhile, image Pz′ has composition including a close-up of a specific child who is substantially at the center of the photograph image. Generally, even if image Pz is observed, it is impossible to judge whether the photographer of the image intentionally selected the wide angle composition without zooming or although he/she originally wanted to obtain an image like image Pz′, an image with such wide angle composition was obtained because the performance of the zoom function of the photography apparatus was limited.